If you write out the abbreviation, experts already know the principle: IMS = IP Multimedia Subsystem. This is a telecommunications system that uses the packet-based Internet Protocol (IP) for multimedia, digital communication.
Because it allows users standardized access to services from different networks.
In other words, in a service-oriented environment, IMS provides the user, i.e. telcos/network operators and their customers, with access to a wide range of applications - regardless of network structure and end device! And as the name suggests, it is all about multimedia, integrated applications for audio, video or data applications.
There remains the question of the meaning of the term "subsystem": IMS, as a subsystem, is an integral part of a complex system called Session Initiation Protocol (SIP). This is a standardized network protocol for voice and video communication in real time. It is integrated into Internet telephony, for example, for establishing and terminating audio/video connections (sessions) via Voice over IP (VoIP) and Voice over New radio (VoNR). In addition, SIP enables pioneering communication services such as web conferencing, application sharing, instant messaging or online gaming, among others.
Conclusion: Without the Session Initiation Protocol and the IP Multimedia Subsystem, unified communications would be unthinkable today.
When it comes to standardization and protocols, the Third Generation Partnership Project (3GPP) inevitably comes into play, having played a major role in the standardization of the IP Multimedia Subsystem. 3GPP is a worldwide cooperation of bodies for standardization in mobile communications, i.e. for UMTS, GSM, LTE and 5G, founded in 1998. In the context of UMTS standardization, 3GPP laid the foundation for IMS as early as 2001. The first specifications for IMS followed with Release 5 - and SIP was already integrated for signaling at that time. With Release 6 and 7, other important features were gradually added: WLAN and fixed network as additional access networks, as well as DRM, services for location determination, and generic user profiles. Further IMS solutions will certainly follow.
Information about the importance of CreaLog Service Manager as a central framework for controlling IMS applications can be found here.